Wednesday, July 30, 2008
Recently researchers have found out (Nature, 9. October 2003 p. 612-614) that many bat species seem to have a sensitivity to ultraviolet (UV) light, which is more abundant at dawn and dusk. The colour-blind Long-tongued Nectar bat (Glossophaga soricina) for instance is sensitive to UV down to a wavelength of 310 nm. Experiments at Universities in Guatemela and Erlangen, Germany revealed a sensitivity in the green (max. 510 nm) and UV (>365 nm) spectra. The same very same photoreceptor was responsible for both peaks in the green and the UV. Quite interesting to note since in all rodents and marsupials with colour vision, there is a separate receptor which handles UV light.
Link to the original publication of the Max Planck Institute, Germany
The University of Ulm, Biology Dept., Germany has decided to equip their two year long lasting Panama expedition, starting spring 2008, together with the US Smithsonian Institute with two calibrated for UV lenses, my X135 and X35, to help to discover the secret of bats with UV sight there. These bats live from fig fruits which are supposed to carry marks only visible in UV.
First interim results now show, that indeed there seems to be UV marks at these fruits which come from the wax coated surface. [click on image to see a larger version]
[top images curtesy and (C) Universtiy of Ulm; processing and UV remapping by me]
Top left shows a sample of that Panamanean fig fruit in visual light, top right in UV light shot using the calibrated for UV X-lenses. Bottom left and right shows UV remapped into the visual domain to enhance the UV pattern present.
["X-lenses" denotes a series of lenses which are calibrated for UV photography. Up to today there are the X28, X35, X50, X90, X135 and longer lenses available, the number after the "X" denoting the focal length. These allow for high quality reflected UV photography at a fraction of the cost of these specialized fluorite/quartz lenses]
So I hope you found that as interesting as I do....
Stay tuned, more will follow on that fascinating subject...
More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos